In-depth metrics + Waterfalls
Slice data by location, browser version, and device type to compare Core Web Vitals scores or performance indicators. Identify specific impact areas on the waterfall to quickly diagnose performance issues.
LCP
Largest Contentful Paint
CLS
Content Layout Shift
FID
First Input Delay
TBT
Total Blocking Time
3 key metrics for checking your site’s health and SEO ranking
Know your site’s health in minutes via using WebPageTest—it’s free.
Understanding site health
through Core Web Vitals (CWV)
Users find websites when they are discoverable.
Your site’s discoverability is determined by many SEO factors — including Core Web Vitals.
LCP
A low LCP score means your user’s experience snappy page speeds throughout your site. This score is measured in miliseconds.
CLS
A low CLS score means your user’s experience is stable and accessible when navigating across layouts, buttons, links, and content.
FID
A low FID or TBT score means your users can quickly start exploring your site’s content without feeling held back by unresponsive actions on buttons and links.
We improved our CLS by >250% with help from WebPageTest’s Highlight Layout Shift.
Chris Boakes
Developer, The Telegraph
Read the case study
Why our users and businesses choose WebPageTest
Exportable, powerful visualizations
Download and share videos, .gifs, and filmstrips with your team for quick collaboration and page optimization planning.
CrUX + Lighthouse data
View representative field data from Chrome User Experience Report at the time of the test and with minimize variability running on the latest Lighthouse version.
Developer-first API & integrations
Scale and 'programmatically run WebPageTest with our easy-to-use API, and integrate into your dev workflows with our easy-to-use API with the NPM wrapper for Node JS, Github Actions, VC Code Extension, Slackbot, Grafana and more.
.jpg)